MI: Antimicrobials 1 Pt.2 Flashcards
What are macrolides particularly useful for?
Mild staph or strep infections in patients who are allergic to penicillin
Recall 2 macrolide antibiotics
Azithromycin
Clarithromycin
What type of bacteria are tetracylines effective against?
They are broad spectrum
Recall a class of antibiotic you should never give to children or pregnant women
Tetracyclines
Recall one side effect of tetracycline antibiotics
Photosensitivity –> Light-sensitive rash (believed to be because tetracycline can absorb UV light and release that energy to skin cells in form of reactive oxygen species)
Recall the broad mechanism of action of macrolides
Bind to the 50s subunit of ribosomes
Recall the broad mechanism of action of tetracyclines
Bind to 30s subunit of ribosomes
*Bacteriostatic - still useful in certain situations, especially with MRSA*
What type of bacteria is chloramphenicol effective against?
Many - it is v broad spectrum
Why is chloramphenicol rarely used?
Risk of aplastic anaemia and grey baby syndrome in neonates due to inability to metabolise drug
*Still useful for meningitis when patients have penicillin anaphylaxis*
Recall 2 specific bacteria that macrolides are effective against
Campylobacter sp
Legionella pneumophila
(macrolides = erythromycin/ azithromycin/ clarithromycin)
Recall the broad mechanism of action of chloramphenicol
Binds to 50s subunit of ribosomes - inhibits formation of peptide bonds during translation
Recall the broad mechanism of action of oxazolidinones
Binds to the 23s portion of the 50s ribosome subunit to prevent 70s subunit formation
Recall two types of bacteria that oxazolidinones are particularly active against
Highly active against gram positive organisms - especially MRSA and VRE
Recall an example of oxazolidinones
Linezolid
Recall one potential side effect of oxazolidinones
Thrombocytopaenia and neurological side effects if used longer than 4 weeks
Which antibiotics inhibit protein synthesis by binding to the:
30s subunit
50s subunit
30s = aminoglycosides, tetracyclines
50s = macrolides, chloramphenicol, oxazolidinones (binds to the 23s portion)
Recall the broad mechanism of action of fluoroquinolones
Act on alpha subunit of DNA gyrase
Recall the uses of fluoroquinolones
Which bacteria types are susceptible
Complicated UTI
Meningococcal chemoprophylaxis
Pneumonia
Atypical pneumonia
Bacterial gastroenteritis
*BROAD SPECTRUM antibacterial activity against gram negatives*
Recall examples of fluoroquinolone antibiotics
Levofloxacin
Moxifloxacin
Ciprofloxacin
How do nitroimidazoles work?
Under anaerobic conditions, an active intermediate is produced which causes DNA strand breakage
Give examples of nitromidazole antibiotics
Metronidazole
Tinidazole
Recall types of organisms that metronidazole is effective against
Anaerobes
Protozoa
When should metronidazole be taken?
Right after visiting the toilet as it sits in bladder
Recall the broad mechanism of action of rifampicin
Binds to DNA-dependent RNA polymerase to inhibit RNA synthesis
Recall the main use of rifampicin
TB treatment
